[PR94044] Fix ICE with sizeof<argumentpack>

[PR94044] Fix ICE with sizeof<argumentpack>

Thanks to Jim for figuring out how to reproduce the problem, I was
able to apply pr94044-jig.diff to poorly hash the specialization
table. (That places all the specializations of a particular template
in the same bucket, forcing us to compare the arguments.)

The testcase creates sizeof_exprs containing argument packs, and we
can no longer use same_type_p on those.

	PR c++/94044
	* tree.c (cp_tree_equal) [SIZEOF_EXPR]: Detect argument pack
	operand.